Patients infected with H. pylori undergo the gastroscopy. During the gastroscopy, gastric mucus samples are collected, from which DNA is extracted. The DNA samples are subjected the full-auto SNP analyzer and the from A to G mutation of 23s rRNA of H. pylori at the positions of 2142 and 2143 is measured. When the mutation is detected, patients are diagnosed to be infected with clarithromycin-resistant strains of H. pylori and therefore, treated with the triple therapy with vonoprazan 20 mg bid + amoxicillin 750 mg bid + metronidazole 250 mg bid for 1 week. When the mutation is not detected, patients are considered to be infected with clarithromycin-sensitive strains of H. pylori and therefore, treated with the triple therapy with vonoprazan 20 mg bid + amoxicillin 750 mg bid + clarithromycin 200 mg bid for 1 week. The success or failure of eradication was determined based on the 13C-urea breath test performed 1 month after the therapy. The total eradication rates with this strategy was compared with that by the standard regimen in Japan performed in the same period of the study.